1 /*
2 * Copyright 2017-2022 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10 /* DH parameters from RFC7919 and RFC3526 */
11
12 /*
13 * DH low level APIs are deprecated for public use, but still ok for
14 * internal use.
15 */
16 #include "internal/deprecated.h"
17
18 #include <stdio.h>
19 #include "internal/cryptlib.h"
20 #include "internal/ffc.h"
21 #include "dh_local.h"
22 #include <openssl/bn.h>
23 #include <openssl/objects.h>
24 #include "internal/nelem.h"
25 #include "crypto/dh.h"
26
dh_param_init(OSSL_LIB_CTX * libctx,const DH_NAMED_GROUP * group)27 static DH *dh_param_init(OSSL_LIB_CTX *libctx, const DH_NAMED_GROUP *group)
28 {
29 DH *dh = ossl_dh_new_ex(libctx);
30
31 if (dh == NULL)
32 return NULL;
33
34 ossl_ffc_named_group_set(&dh->params, group);
35 dh->params.nid = ossl_ffc_named_group_get_uid(group);
36 dh->dirty_cnt++;
37 return dh;
38 }
39
ossl_dh_new_by_nid_ex(OSSL_LIB_CTX * libctx,int nid)40 DH *ossl_dh_new_by_nid_ex(OSSL_LIB_CTX *libctx, int nid)
41 {
42 const DH_NAMED_GROUP *group;
43
44 if ((group = ossl_ffc_uid_to_dh_named_group(nid)) != NULL)
45 return dh_param_init(libctx, group);
46
47 ERR_raise(ERR_LIB_DH, DH_R_INVALID_PARAMETER_NID);
48 return NULL;
49 }
50
DH_new_by_nid(int nid)51 DH *DH_new_by_nid(int nid)
52 {
53 return ossl_dh_new_by_nid_ex(NULL, nid);
54 }
55
ossl_dh_cache_named_group(DH * dh)56 void ossl_dh_cache_named_group(DH *dh)
57 {
58 const DH_NAMED_GROUP *group;
59
60 if (dh == NULL)
61 return;
62
63 dh->params.nid = NID_undef; /* flush cached value */
64
65 /* Exit if p or g is not set */
66 if (dh->params.p == NULL
67 || dh->params.g == NULL)
68 return;
69
70 if ((group = ossl_ffc_numbers_to_dh_named_group(dh->params.p,
71 dh->params.q,
72 dh->params.g)) != NULL) {
73 if (dh->params.q == NULL)
74 dh->params.q = (BIGNUM *)ossl_ffc_named_group_get_q(group);
75 /* cache the nid and default key length */
76 dh->params.nid = ossl_ffc_named_group_get_uid(group);
77 dh->params.keylength = ossl_ffc_named_group_get_keylength(group);
78 dh->dirty_cnt++;
79 }
80 }
81
ossl_dh_is_named_safe_prime_group(const DH * dh)82 int ossl_dh_is_named_safe_prime_group(const DH *dh)
83 {
84 int id = DH_get_nid(dh);
85
86 /*
87 * Exclude RFC5114 groups (id = 1..3) since they do not have
88 * q = (p - 1) / 2
89 */
90 return (id > 3);
91 }
92
DH_get_nid(const DH * dh)93 int DH_get_nid(const DH *dh)
94 {
95 if (dh == NULL)
96 return NID_undef;
97
98 return dh->params.nid;
99 }
100
